1. Field of the Invention
The invention concerns the field of lighting devices, in particular for motor vehicles, and more particularly relates to headlamps equipping these vehicles. More specifically, the invention relates to the methods of electrical connection between an optical module equipping a motor vehicle headlamp and remote devices which are equally placed inside and/or outside the headlamp.
2. Description of the Related Art
Motor vehicle headlamps are generally composed of a housing which is closed by a transparent wall, through which one or more light beams emerge. This housing accommodates one or more optical modules which are assembled inside the housing by means of a bracket arranged in a chassis, plate or any other similar intermediate device which can bracket the optical module(s) and which is configured for their assembly inside the housing. Such a bracket can be an individual bracket assigned to one optical module or a collective bracket holding a plurality of these individual brackets. The optical modules each comprise a light generator comprising at least one light source associated with an optical system. The light source is any device able to emit light, such as a filament bulb, a gas-discharge bulb or also a device combining one or more light-emitting diodes (LEDs) which are advantageously clustered on a common electronic bracket. The optical system can modify at least one parameter of the light generated by the light source in order to emit the light beam by the optical module. The optical system comprises optical components such as a reflector, lens, diffuser, collimator or any other device that can modify at least one of the parameters of the light generated by the light source, such as its average reflection and/or its direction, or even a combination of a plurality of these elements. The optical module is equipped with various devices necessary for its operation, such as means to activate the light source(s) which it comprises, means of cooling and a substructure to carry all the components of the optical module. This substructure is used for assembling the optical module inside the housing by means of the bracket at least.
Among the optical modules intended to equip motor vehicle headlamps, some can be movably assembled on the housing. For example, the movable optical module is used for a dynamic bending light function (DBL), according to which the optical module is movably assembled on the housing with lateral reflector movement relative to the general axis of forward movement of the vehicle or longitudinal axis of the vehicle. These DBL functions can be applied to low beam functions, then called bending light or dynamic bending light (DBL), or to high beam functions, again called high beam DBL. For example, yet another known function lies in the dynamic range levelling of the optical module based on assembling the optical module so that it can move on the housing relative to the resting plane of the vehicle on the ground. Other complex functions are also known, according to which various optical modules are movably assembled on the housing and cooperate together in order to obtain selective illumination of the traffic lane, in particular in order to avoid dazzling users of other oncoming vehicles or those being followed.
The optical module(s) are movably assembled on the housing by means of the bracket(s) which are allocated to them. Generally, it is to be considered that a movable optical module can be movably assembled so as to swivel on the housing about at least one axis corresponding to one of the directions in Euclidean space. The movable assembly of the optical module can be implemented according to various and non-specific embodiments, but inevitably induces the ability to move on other devices which are movably assembled jointly with the optical module. In particular, such devices are electrical devices individually fixed on one or more optical modules, such as the light sources and their means of activation, sensors and/or one or more electric motors.
There arises the problem of electrical connection between the devices fixed on the optical module and/or movably assembled jointly with the latter, with other devices which are arranged at a distance from the optical module. For example, the control means for operating the optical module are usually implemented at a distance from the latter, in any available space of the housing even outside the headlamp. In addition, the source of energy supply to the optical module is usually a remote source equipping the vehicle.
Usually, this electrical connection between the fixed and/or movable devices and the remote devices is provided by means of conductors with at least one electric flux. These electric fluxes in particular correspond to an electric current, a control signal or any other data signal that can be exchanged between the optical module and the remote electrical devices. Such conductors are in particular made of wire or cable.
Technological developments have complicated the methods of using the optical modules in order to provide them with advantageously new capabilities and functions, the number of electric fluxes inevitably increasing. For example, the methods for activating the light source(s) are increasingly sophisticated, in particular based on the selective activation of the LEDs used to generate the light emitted by the headlamp. Certain elliptical modules also comprise movable covers to modify the shape of the beam generated by the module, their control can be complex to a greater or lesser degree and numerous electric fluxes must be conducted to the module.
According to a traditional technique, the conductors are combined in at least one multi-cable hose. This assembly, in the present application, is called round cable. Such a hose has the advantage of being robust but the disadvantages of being rigid and comprising a limited number of cables. The rigidity of the cables is not favorable as regards the freedom of movement of the optical module, and their restricted number limits the potential amount of electric fluxes which they can conduct.